Implementations of the claimed invention generally may relate to processors, and in particular to instructions for causing processors to perform Advanced Encryption Standard (AES) encryption or decryption.
AES is the advanced encryption standard from the National Institute of Standards and Technology (NIST), and is defined in FIPS Publication 197. AES may have a variable key size. There are 3 acceptable key sizes: 128-bit, 192-bit and 256-bit. AES encryption takes 128-bits plaintext input and a key, and then produces 128-bits of ciphertext (e.g., plaintext that has been AES encrypted) output. Similarly, AES decryption performs an opposite operation where it takes 128-bits ciphertext and a key to produce 128-bits of plaintext.
AES may be used in many modes of operation. One of the more common modes is the so-called Cipher-Block Chaining (CBC) mode. A somewhat less common mode is the so-called Electronic Codebook (ECB) mode. Other modes are also possible, such as the emergent so-called Counter mode (CTR), which is conceptually similar to ECB.
In computing systems, it may be desirable to have an instruction or instructions for a processor that is dedicated to AES encryption and/or decryption.